The Bronze Thief

 is a quest in Tyranny.

Synopsis
Raetommon has taken both the Magebane Helm and Forge Master Zdenya - Graven Ashe will not be happy that his prize Forge-Bound and the artifact are gone. Pursue Raetommon and retrieve both Zedyna and the Helm.

Walkthrough

 * Talk to Eldian to learn of the Bronze Brotherhood operations at the Twin Rivers camp. Start your search there.
 * Once you arrive, it turns out that the mercenaries are fighting the Bane. Brother Caelus pleads with you for help. Since you're hostile with the Brotherhood, your only option is to attack.
 * Find Welby on the other side of the river, to the northeast. She will reveal that Raetommon had gone inside the Oldwalls at Twin Rivers. She also says that a man named Myrek has the Keystone required to get inside the Oldwalls - Myrek was headed toward Deserter's March. Find him there.
 * Head directly north to find Locke and Myrek arguing. Eliminate them to claim the keystone.
 * Return to Twin Rivers. Use the Oldwalls Keystone on the entrance and go in. This completes the quest.